OBJECTIVE: To analyze the indicators of exclusive breastfeeding (EB) in Brasilia's University Hospital (BUH) during a 10-year interval and to verify associated factors to early weaning. METHODS: A retrospective cross-sectional study was conducted by chart review of children attending the Pediatric Clinic during 1999 and 2008. The duration of exclusive breastfeeding was categorized at four months and four months or more. Prevalence ratios for early weaning (EB<4 months) were estimated with a model of Poisson regression and robust variance. Non-parametric Mann-Whitney test was used to compare the exclusive breastfeeding duration in the studied years. RESULTS: Among 2,173 patients, 1,443 in 1999 and 730 in 2008. There was an increase from 110.7 to 123.6 days in the duration of EB. A significant association between maternal education and early weaning was shown, with a 12.6% higher prevalence in mothers with less than eight years of schooling compared to those with 11 or more years. No other associations were found in the study. CONCLUSIONS: Similarly to what was found in Brazilian capitals and Brasilia, there was an increase in the length of exclusive breastfeeding related to mother educational level. Nevertheless, the duration exclusive breastfeeding is still below the threshold of 180 days recommended by the World Health Organization.